This invention relates in general to the field of semiconductor manufacturing and more particularly to a system and method for using a capacitance measurement to monitor the manufacture of a semiconductor.
Metal capacitance is important to the functionality, performance, and reliability of integrated circuits. Thus, the ability to closely monitor the manufacture of integrated circuits and semiconductors is similarly important. Semiconductor characteristics or parameters that vary significantly from their designated values may cause significant problems in systems or architectures with precise or exact specifications. Elements such as metal thickness, metal width, metal spacing, and dielectric thickness each represent essential criterion to be controlled during the semiconductor manufacturing process. When system parameters become skewed because of inaccurate test results or errors in the manufacturing process, the byproduct may be incompatibility with neighboring components, poor performance, or the non-operation of associated devices.
Monitoring each layer of semiconductor formations during the manufacturing process may be performed by using methods that cut or section the actual product being manufactured. However, these destructive methods are costly in that they sacrifice semiconductor regions that would otherwise be used or sold. In addition, such methods do not offer the ability to share or to transfer precise information relating to existing or new design processes. The inability to share newly developed design concepts or new fabrication techniques may limit or add time and expense to the manufacturing process.
From the foregoing, it may be appreciated by those skilled in the art that a need has arisen for an improved monitoring approach that provides for effective scrutiny offered during the semiconductor manufacturing process. In accordance with one embodiment of the present invention, a system and method for using a capacitance measurement to monitor the manufacture of a semiconductor is provided that substantially eliminate or greatly reduce disadvantages and problems associated with conventional simulation, design, and measurement techniques.
According to one embodiment of the present invention, there is provided a method for using a capacitance measurement to monitor the manufacture of a semiconductor that includes positioning a measurement circuit in a scribe line area associated with the semiconductor. The scribe line area is indicative of a delineation that separates one or more portions of the semiconductor. A capacitance of one or more elements included within the one or more portions of the semiconductor is then measured using the measurement circuit. The method also includes comparing the capacitance measurement of the one or more elements included within the one or more portions of the semiconductor to a reference set of capacitance values such that a parameter associated with a manufacturing process that generated the semiconductor may be checked.
Certain embodiments of the present invention may provide a number of technical advantages. For example, according to one embodiment of the present invention, a measurement approach is provided that allows highly accurate capacitance measurements to be obtained for a semiconductor as it propagates through the manufacturing process. The enhanced accuracy of the capacitance measurement is a result of the elimination of capacitances between elements or conductors of a device under test. The elimination of their capacitance is achieved by charging and discharging multiple conductors in phase and thus effectively shorting neighboring conductors proximate to a conductor being targeted for the capacitance measurement. Accordingly, the capacitances of associated or neighboring elements that may otherwise act to negatively influence a capacitance measurement are negated or otherwise removed from the measurement equation. The enhanced capacitance measurement provides the opportunity to more closely monitor the manufacture of a semiconductor.
Another technical advantage of one embodiment of the present invention is a result of the efficient use of the scribe line area, which would otherwise be sacrificed when integrated circuits are divided or sectioned into multiple portions. The capacitance of one or more target conductors to one or more selected conductors in a multiple-conductor structure may be measured, whereby the capacitance value may be converted into a capacitance per unit length. This unique capacitance may then be compared with simulation values in order to determine whether or not the semiconductor manufacturing process is adequate for its intended design. Such a monitoring function may be critical where specifications or design standards are designated to be within certain ranges or within specified parameters.
Yet another technical advantage of one embodiment of the present invention is a result of the unique capacitance measurement obtained by the measurement circuit. The unique capacitance measurement may be used as an identification tag for persons or entities wishing to identify a semiconductor structure by using its associated capacitance value. In this sense, the unique capacitance parameter operates as an identifier indicative of the unit or component associated with that capacitance value. This unique identification may further provide for optimal communications between entities wishing to glean information about a semiconductor device, component, element, or object. Embodiments of the present invention may enjoy some, all, or none of these advantages. Other technical advantages may be readily apparent to one skilled in the art from the following figures, description, and claims.